#include <bits/stdc++.h>
using namespace std;
#define N 1010
#define ll long long
#define fs first
#define sc second
#define ii pair<ll,int>
#define pb push_back
#define int ll
int n,m,k,buy[N][N],sell[N][N],cost[N][N],dis[N][N],ktr[N][N];
vector<ii>g[N];
ll get_cost(int u,int v)
{
ll res=-1e18;
for(int i=1;i<=k;i++)
if(buy[u][i]!=-1&&sell[v][i]!=-1)
res=max(res,sell[v][i]-buy[u][i]);
return res;
}
void dijkstra(int S)
{
priority_queue<ii>s;
dis[S][S]=0;
s.push({0,S});
while(!s.empty())
{
ii cc=s.top();
s.pop();
ll L=-cc.fs;
int u=cc.sc;
if(ktr[S][u]==1)
continue;
ktr[S][u]=1;
for(auto v:g[u])
if(dis[S][v.sc]>L+v.fs)
{
dis[S][v.sc]=L+v.fs;
s.push({-dis[S][v.sc],v.sc});
}
}
}
ii dp[N];
bool check(int X)
{
for(int i=1;i<=n;i++)
dp[i]={0,0};
for(int t=1;t<=n;t++)
{
for(int u=1;u<=n;u++)
for(int v=1;v<=n;v++)
if(u!=v&&dis[u][v]<1e12)
{
dp[v]=max(dp[v],ii{dp[u].fs+max(0ll,cost[u][v])-dis[u][v]*X,dp[u].sc+1});
}
}
//cout<<cost[1][4]<<endl;
// for(int i=1;i<=n;i++)cout<<dp[i].fs<<" "<<dp[i].sc<<endl;
for(int u=1;u<=n;u++)
for(int v=1;v<=n;v++)
if(u!=v&&dis[u][v]<1e12)
{
if(dp[v]<ii{dp[u].fs+cost[u][v]-dis[u][v]*X,dp[u].sc+1})
return 1;
}
return 0;
}
int32_t main()
{
#ifdef SKY
freopen("A.inp","r",stdin);
freopen("A.out","w",stdout);
#endif // SKY
ios::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin>>n>>m>>k;
for(int i=1;i<=n;i++)
for(int j=1;j<=k;j++)
cin>>buy[i][j]>>sell[i][j];
for(int i=1;i<=m;i++)
{
int u,v,L;
cin>>u>>v>>L;
g[u].pb({L,v});
// g[v].pb({L,u});
}
memset(cost,-0x3f3f,sizeof(cost));
memset(dis,0x3f3f,sizeof(dis));
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
cost[i][j]=get_cost(i,j);
for(int i=1;i<=n;i++)
dijkstra(i);
// cout<<check(2)<<endl;return 0;
int l=1,r=1e9,res=0;
while(l<=r)
{
int mid=(l+r)/2;
if(check(mid))
{
res=mid;
l=mid+1;
}else
r=mid-1;
}
cout<<res;
return 0;
}
